Answer:
Correct option a) True.
Step-by-step explanation:
It is true since the Vickers hardness value refers to the force applied in a 136 ° diamond tip penetrator divided by the surface of the groove produced in the material, the lower the impression made on this greater the value will be end of the Vickers measurement and greater its hardness.
The equation to determine the Vickers hardness value will be:
Hv= ((1.854 × P)/(d²)) (kg/mm²)
Therefore a value of 220 Vickers refers to a harder material than another value of 180 Vickers.